DECLARE	@delimiter VARCHAR(32) = ', '

-- for each table, build list of columns, delimited by a string

SELECT TABLE_NAME

	-- remove leading delimiter
	, STUFF(column_list, 1, DATALENGTH(@delimiter), '') AS column_list
FROM (
	SELECT TABLE_NAME
	
		-- concatenate all column names in order
		, (SELECT @delimiter + COLUMN_NAME
			FROM INFORMATION_SCHEMA.COLUMNS
			WHERE TABLE_NAME = t.TABLE_NAME
			ORDER BY ORDINAL_POSITION
			FOR XML PATH('')) AS column_list
			
	FROM INFORMATION_SCHEMA.TABLES t
) t
ORDER BY TABLE_NAME
